Posted 09 August 2010 - 01:00 AM
Thanks for the review - it has been helpful.
However, you seem to be somewhat confused about the nature of the current generation of Advanced Format drives.
Firstly, they are 4k sectors internally - but externally they expose exactly the same 512 byte SATA interface as non-Advanced Format drives. i.e. they do not need drivers and there is no special support for them in Vista, Win 7, OS X or Linux. The reason that these OS's work so well with AF drives is because they naturally align their partitions on 4k boundaries - and this means that their clusters line up with the internal sectors. e.g Vista and Win 7 partitions start on the 1MB boundary.
Windows XP, by comparison, creates it's first partition at sector 63 - which is not a 4k boundary (it's out by 1), and therefore as it reads a cluster from the disk (using multiple 512-byte sector reads) the disk has to read 2 sectors from the disk since the cluster spans 2 sectors - and this is the only drawback with AF drives - a performance penalty when using unaligned partitions. To fix this, the WD Align tool shifts XP partitions to a 4k boundary - easy. Alternatively, you can use a jumper on pins 7 & 8 on the drive which offsets of the sector numbers by 1 (so that when you read sector 1 you are really getting sector 2 - and the real sector 0 is unaddressable) - and this has the effect of putting "sector 63" at sector 64 and therefore aligns XP partitions.
The WD Align tool does not provide "512-byte emulation" as claimed and there are other ways to achieve alignment on a 4k boundary. One example is when moving your existing XP partition to an AF drive using Symantec Ghost, use the "-align=1mb" command line switch when restoring the image and Ghost will align the partition for you.
So I am not really sure what the review tells us when it is comparing the WD20EARS non-4k - it's not useful data, as you have to go out of your way to make it perform badly, and the performance hit would apply to any AF drive when used with non-aligned partitions.
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